High tensile vanadium alloys



United States Patentff O.

HIGH TENSILE VANADIUM ALLOYS William Rostoker, Oak Lawn, Ill., assignor to Amour Research Foundation of Illinois Institute of Technology, Chicago, Ill., a corporation of Illinois N Drawing. Application April 4, 1955, Serial No. 499,229

8 Claims. (Cl. 75-134) The present invention is directedto improvements in high tensile alloys, and is more specifically directed to alloys containing substantial amounts of vanadium.

Substantially pure vanadium metal has only a fair tensile strength and only a fair amount of ductility, as evidenced from the following table which illustrates typical mechanical properties of substantially pure vanadium:

TABLE I At room temperature:

, Ultimate tensile strength 49,100 p. s. i.

Reduction in area 2.4%.- Elong'ation 6.0%.

Modulus of elasticity 19.7)(10 p. s. i. Hardness Q. 182 VHN. Ultimate tensile strength at 700 C 25,500 p. s. i. Ultimate tensile strength at 900 C 15,320 p. s. i.

The tensile strength of substantially pure vanadium is considerably lower than other metals and alloys used for structural elements, as evidenced from the following comparison with various commonly employed alloys:

TABLE 11 Ultimate Tensile Strength,

Composition Steel coutaining 13% Ni, 13% Cr, 2.5% W, 2%

Mo, 3 Cb, 1% C, 0.4% O Steel containing 25% Cr, 15% Ni Steel containing Or, Ni, 1.5% Tl. 60%, Co, 28% Cr, 6% Mo, 3% Ni, 2% Fe, 0.25% 45% Co, 20% N, 20% Cr, 4% Ch, 4% W, 4%

, 3% Mo, 0.47% o 2,805,153 Patented Sept; 3, 1957 Preferably, the titanium content is in the range from about 40% to 50%, the chromium content is preferably from 5 to 10%, the aluminum content is preferably 5 to 10%, and the silicon content is preferably from 1 to 5 An object of the present invention is to provide an improved series of vanadium base alloys having excellent tensile strength properties.

Another object of the invention is to provide vanadium 7 high temperature environments.

The metallic vanadium employed in making the alloys of the present invention was produced by the calcium reduction of vanadium pentoxide. The metal employed had a sufiiciently low concentration of interstitial compounds and metallic impurities to permit severe mechanical deformation, both in the hot and cold condition. The chemical analysis of the vanadium indicated that the carbon content was about 0.077%, oxygen 0.056%, nitrogen 0.086%, and hydrogen 0.002%.

All alloys were produced by melting of the elemental components in the proper proportions in a non-consumable electrode, water cooled, copper crucible arc melting furnace. Cast ingots of the alloy were forged to onehalf inch diameter rods for machining directly to tensile test pieces.

Shoulder type tensile test pieces were machined from one-half inch diameter forged rods to a test diameter of 0.252 inch, agauge length of one inch, and an overall length of three inches. Testing was performed in a conventional Baldwin-Southwark, hydraulically operated, universal testing machine. At temperatures above 500 C., the alloys were protected from oxidation by providing an upward current of argon gas around the test piece.

In substantially all cases, the addition of small, controlled amounts of chromium, silicon, or aluminum significantly increased the tensile strength of the vanadiumtitanium alloy without significantly decreasing the ductility of the alloy. In many cases, the ductility was significantly improved by the addition of one of more of the three named elements.

As an example of the foregoing, an alloy consisting solely of vanadium and 20% titanium had a measured ultimate tensile strength of about 95,000 pounds per square inch at room temperature. The addition of 5% aluminum, in replacement of a corresponding amount of vanadium, brought the ultimate tensile strength, at room temperature to about 130,000 pounds per square inch. Similarly, an alloy of 70% vanadium and 30% titanium had an ultimate tensile strength of 112,000 pounds per square inch which was raised to a value of 140,000 pounds per square inch upon the addition of 5% aluminum in replacement of a corresponding amount of the vanadium. In the case of chromium, the addition of 5% chromium to a vanadium-titanium alloy containing 20% titanium raised the tensile strength to 114,600 p. s. i. at room temperature. The addition of only 1% silicon to a vanadium-titanium alloy containing 30% titanium was effective to raise the ultimate tensile strength at room temperature to 126,400 p. s. i.

The substantial improvements achieved in the tensile properties of the alloys of the present invention are illustrated in the following table at various titanium contents,

anda't various contents of the third metal, the balance of the alloy in each case being substantially pure vanadium:

TABLE III V Ultimate Elonga Reduction Composition T. C. Tensile tion, in Area, Strength, percent percent p. s. i.

2011-5Gr Room Temp; 114, 000 28.1 21.8 20Ti-50r 700 91, 800 18. 3 18. 8 56, 000 1'1. 1 12. T 43, 200 29. 7 10.0 131, 000 12. 5 6. '10, 200 14.1 S. 8 40Ti-'-5Cr 900 38, 000 17. 2 ll. 1 i-50r. Room Temp. 130, 000 9. 4 9. 6 700 06, 200 17.2 7. 2 Room Temp 153, 600 4:0 7. 1 700 82, 000 7.0 4. 2 900 31, 800 31. 3 15. Room Tcmp 126, 400 12. 5 10. 8 Room Temp 151,000 18. 8 25. 0 Room Temp 132, 000 14. O 15. 4 Room Temp 150, 000 12. 5 17. 5 Room Temp 160, 200 4. 7 2.8 700 60. 9 36. 9 17. 2 25. 2 l2. 5 15. 3 96.78 05 '26. 2 4G. 1 103. 1 95 9. 4 16:7 40'11-5Al 28.2 25. 2

From. the foregoing, it will be evident that the alloys of the present invention exhibit excellent tensile strength both at room temperatures and at elevated temperatures on the order of 700 or 900 C. At the Same time, the ductility of the vanadium alloy does not appear to be adversely aflected by the addition of the elements aluminum, silicon, or chromium, and in many cases the ductility is improved by the addition.

It will be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.

I claim as my invention:

. 1. A high tensile strength alloy containing titanium in amounts from 20 to 50% by weight, a'significant-amount of a metal selected from the group consisting of aluminum,

'SiIiCQIL'aHd chromium in amounts up to 10% by weight,

and the balance being substantially all vanadium.

2. A high tensile strength alloy containing titanium in amounts from about 40% to about by weight, a significant amount of a metal selected from the group consisting of aluminum, silicon, and chromium in amounts up to 10% by weight, and the balance being substantially all vanadium.

3. A high tensile strength alloy containing titanium in amounts from 20 to 50% by weight, chromium in amounts from 5 to 10% by weight, and the balance being substantially all vanadium. V 4. A high tensile strength alloy containing titanium in amounts from 20 to 50% by weight, aluminum in amounts from 5 to 10% by weight, and the balance being substantially all vanadium.

5. A high tensile strength alloy containing titanium in amounts from 20 to 50% by weight, silicon in amounts from 1 to 5% by weight, and the balance being substantially all vanadium. V

6. A high tensile strength alloy containing titanium in amounts from 40 to 5 0% by weight, chromium in amounts from 5 to 1 0% by weight, and the balance being sub- -stantia1ly all vanadium.

References Cited in the file of this patent FOREIGN PATENTS Germany Mar. 25, 1942 OTHER REFERENCES WADC Technical Report 52-145, Exploration of vanadium base alloys, Rostoker et al. May 1953, page 5. 

1. A HIGH TENSILE STRENGHT ALLOY CONTAINING TITANIUMM IN AMOUNTS FROM 20 TO 50% BY WEIGHT, A SIGNIFICANT AMOUNT OF A METAL SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, SILICON, AND CHROMIUM IN AMOUNTS UP TO 10% BY WEIGHT, AND THE BALANCE BEING SUBSTANTIALLY ALL VANADIUM. 